tbuckley/cabot-search huggingface dataset:
Abstract P3022: Multiscale Characterization Of Left Ventricular Diastolic Dysfunction In Diabetic And Cardiac Myosin Binding Protein-C Phospho-Ablated Murine Models
Authors: Sunder Neelakantan, Mohit Kumar, Rohit Singh, Sheryl E Koch, Jack Rubinstein, Aaron J Burton, Sakthivel Sadayappan, Reza Avazmohammadi
Journal: Circulation Research (2022)

Introduction: Left ventricular (LV) diastolic dysfunction (LVDD) is often characterized by organ-level (global) metrics whose quantitative connections to mechanical remodeling events at the tissue and fiber levels remain poorly studied. Methods: We performed measurements in the LV at three length scales, namely, organ, tissue, and fiber, in two murine models of LVDD: (i) diabetic (db/db) (n=10) versus wild-type (WT; n=10) mice, and (ii) novel knock-in cardiac myosin binding protein-C (cMyBP-C) phospho-ablated (KI-3A; n=8) versus cMyBP-C phospho-mimetic (KI-3D, n=6) and WT (n=8) mice. Echocardiography was done in vivo. Left ventricular free wall (LVFW) specimens were harvested and passively stretched along with circumferential (C) and longitudinal (L) directions (schematically identified in Fig. 1c) in select mice. Passive tests were followed by activation-relaxation tests of the LVFW specimens at resting biaxial stretches. Active force-pCa measurements at resting stretch were carried out on the skinned papillary muscle fibers. Results: Both db/db and KI-3A mice demonstrated slow relaxation at the organ level indicated by increased E/e' (Figs. 1a-b). db/db LVFW specimens showed increased circumferential stiffness at the tissue level under biaxial passive stretching (p&lt;0.05 for strains &gt;0.25). Biaxial activation-relaxation tests of LVFW specimens in knock-in mice (Fig. 1c shows the results for KI-3A mice) revealed that KI-3A mice relax significantly slower than KI-3D mice along the longitudinal direction (Fig. 1d). Fiber-level tests demonstrated that active force development was significantly enhanced in db/db mice (Fig. 1e) while it was significantly suppressed in KI-3A mice relative to KI-3D and WT mice (Fig. 1f). Conclusions: Although both db/db and KI-3A mice showed LVDD at the organ level, they demonstrated different mechanical alterations at the fiber and tissue fiber levels, suggesting that global metrics should be complemented with metrics characterizing the LV properties at the fiber and tissue levels to fully characterize LVDD.
Abstract P2037: Activation Of A2A Adenosine Receptor Reduces Cardiac Dysfunction Resulting From Pulmonary Hypertension In Rats
Authors: Jaqueline S Da Silva, Bruna Rocha, Gabriel F Gomide, Bianca Nascimento-Carlos, Tadeu Montagnoli, Bruno E Dematté, Rodolfo Maia, Eliezer J Barreiro, Gisele Zapata-Sudo
Journal: Circulation Research (2022)

Pulmonary hypertension (PH) is characterized by extensive pulmonary vascular remodeling, leading to right ventricle (RV) hypertrophy and dysfunction. This work evaluates the hypothesis that the activation of adenosine A2A receptor (AR-A2) by LASBio-1900 could interfere with the cardiac and vascular dysfunction on monocrotaline (MCT)-induced PH in rats. After 14 days of PH induction using a single injection of MCT (60 mg/kg i.p.), twelve male Wistar rats were randomly divided in groups and treated orally either with vehicle or LASSBio-1900 (180 μmol/kg/day). Hemodynamic parameters were obtained using the echocardiography and summarized in table 1. LASSBio-1900 reduced RV hypertrophy observed in PH because the Fulton index altered from 55.4 ± 2.3 to 35.3 ± 5.9% (p&lt;0.05). HP increased RV systolic and diastolic pressure from 19.2 ± 2.0 and 4.7 ± 1.0 to 51.5 ± 5.2 and 11.9 ± 1.3 mmHg, respectively. Ventricular dysfunction was recovered with LASSBio-1900 treatment reducing pressures to 28.4 ± 4.0 and 6.5 ± 0.8 mmHg, indicating improvement of RV dysfunction. Pulmonary arteriole (PA) muscularization was evaluated by alpha- smooth muscle actin stained and vessel medial wall area was expressed as the percentage of the portion positively stained relative to total transversal area. The increase of the wall thickness of distal PA from 61.7 ± 1.1 to 83.24 ± 1.82 % was reduced by LASSBio-1900 (75.2 ± 3.4 %). Perivascular collagen in PA was evaluated through picrosirius red staining and interstitial fibrosis was measured by obtaining the total collagen area per arteriole area. PH increased the perivascular collagen deposition in 15.1 ± 1.3% however, treatment with LASSBio-1900 reduced to 8.7 ± 1.4% (p&lt;0.05). Intense inflammation process on PH was confirmed with the increase of iNOS expression from 4.5 ± 0.3 (control) to 19.0 ± 0.9% (p&lt;0.05) with reduction to 8.7 ± 1.4% when treated with LASSBio-1900. In conclusion, the agonist of AR-A2, named LASSBio-1900 improved RV function and pulmonary structural alteration in PH, indicating a new alternative for treatment of PH-induced RV dysfunction.
Abstract GS109: Ponatinib-induced Cardiotoxicity Is Driven By S100A8/A9-NLRP3-IL1β Signaling Mediated Excessive Inflammation
Authors: Tousif Sultan, Anand P Singh, Prachi Umbarkar, Cristi Galindo, Nicholas Wheeler, qinkun zhang, Sumanth D Prabhu, Hind Lal
Journal: Circulation Research (2022)

Background: The tyrosine kinase inhibitor (TKI) ponatinib is the oral drug for the treatment of chronic myelogenous leukemia (CML) patients with T315I (gatekeeper) mutation. Pharmacovigilance analysis of FDA and WHO datasets have revealed that ponatinib is the most cardiotoxic agent among all FDA-approved TKIs in a real-world scenario. However, the mechanism of ponatinib-induced cardiotoxicity is unknown. The cardiotoxic effects of ponatinib remained hidden in preclinical studies and were only revealed in phase 2 clinical studies and by the subsequent meta-analysis. The lack of well-optimized mouse models has hampered the in vivo cardio-oncology studies. To this end, here we aimed to investigate the hidden cardiotoxic mechanism of ponatinib and strategies to prevent the cardiotoxic manifestations. Methods: We employed wild-type C57BL/6, cardiovascular (CV) comorbidity models e.g., transverse aortic constriction (TAC)-pressure overload (cardiac comorbidity) and high-fat diet-fed ApoE -/- (vascular comorbidity), to investigate the cardiotoxic mechanism of ponatinib. Echocardiography was performed to assess cardiac function. Comprehensive immune profiling was performed to identify ponatinib-induced immune activation using flow cytometry analysis and cytokine assay. Results: Echocardiographic assessment of ponatinib treated high-fat diet-fed ApoE -/- and pressure overload (PO) murine model showed a significant decline in cardiac function, suggesting the key role of CV-comorbidities in ponatinib-induced cardiomyopathy. A combination of multiple in vitro and in vivo models was employed to delineate the underlying molecular mechanisms. An unbiased RNA-Seq analysis identified the enrichment of dysregulated inflammatory genes, including a multi-fold upregulation of alarmins S100A8/A9 as a top hit in ponatinib-treated hearts. Mechanistically, we demonstrate that ponatinib activates the S100A8/9-TLR4-NLRP3-IL-1β signaling pathway in cardiac and systemic myeloid cells (monocytes and neutrophils), in vitro and in vivo , thereby leading to excessive myocardial and systemic inflammation. Excessive inflammation was central to the cardiac pathology because interventions with broad-spectrum immunosuppressive glucocorticoid dexamethasone or direct NLRP3 inhibitor Cy-09 nearly abolished the ponatinib-induced cardiac dysfunction. Taken together, these findings uncover a novel mechanism of ponatinib-induced cardiac inflammation leading to cardiac dysfunction. Conclusions: These findings uncover a novel mechanism of ponatinib-induced cardiac inflammation leading to cardiac dysfunction. Our results provide critical preclinical data and rationale for a clinical investigation into immunosuppressive interventions to mitigate ponatinib-induced cardiotoxicity.
Abstract P1118: Genetic Validation Of Cardiac Cytoskeleton And Extracellular Matrix Targets For Drug Discovery
Authors: Bohdan B Khomtchouk, Michael H Davidson
Journal: Circulation Research (2022)

Currently, cardiovascular disease (CVD) drug discovery has focused primarily on addressing the inflammation and immunopathology aspects inherent to various CVD phenotypes such as cardiac fibrosis and coronary artery disease. However, recent findings suggest new biological pathways for cytoskeletal and extracellular matrix (ECM) regulation across diverse CVDs, such as the roles of matricellular proteins (e.g. tenascin-C) in regulating the cellular microenvironment. The success of anti-inflammatory drugs like colchicine, which targets microtubule polymerization, further suggests that the cardiac cytoskeleton and ECM provide prospective therapeutic opportunities. In this Abstract, we will present genetic validation evidence supporting the efficacy of pharmaceutical modulation of the cytoskeleton and the associated ECM that supports its cellular architecture to find new computationally-derived therapeutics in the treatment of CVD using integrated in-silico, in-vitro, and in-vivo methods. Our focus will be on the dynamic role that the cytoskeleton and ECM play in CVD pathophysiology, highlighting how novel target discovery in cytoskeletal and ECM-related genes enables new therapeutics development to alter the regulation of cellular architecture in plaque formation and rupture, cardiac contractility, and other molecular mechanisms.
Abstract P2004: Beta-Hydroxybutyrate Attenuates Heart Failure With Reduced Ejection Fraction Via Epigenetic Regulation Of Pgc1α
Authors: Stanislovas S Jankauskas, Jessica Gambardella, Fahimeh Varzideh, Urna Kansakar, Pasquale Mone, Simone Sidoli, Gaetano Santulli
Journal: Circulation Research (2022)

Mitochondrial dysfunction plays a crucial role in the pathogenesis of heart failure with reduced ejection fraction (HFrEF). The ketone body beta-hydroxybutyrate (BHB) was suggested to improve mitochondrial function. However, the mechanisms are not fully understood and no studies investigated BHB effect on mitochondrial dysfunction and cardiac insufficiency in HFrEF. HFrEF was modeled in mice by permanent occlusion of the left anterior descending coronary artery causing myocardial infarction (MI). After surgery, mice were fed with BHB diet or standard chow. Sham operated mice on standard chow served as a control. BHB diet increased BHB plasma level 2.75 times compared to mice on standard chow. Four weeks after MI, BHB diet significantly improved cardiac remodeling, evident by decreased myocardial fibrosis, higher ejection fraction, lower left ventricular diastolic volume, and robust downregulation of atrial natriuretic peptide. Strikingly, survival rate was 25% for mice on normal chow and 60% for mice on BHB-diet. In primary isolated cardiomyocytes, we observed that BHB diet also shortened sarcomere time to peak contraction. Basal and maximal cardiac mitochondria respiration was reduced 4 weeks after MI alongside with downregulation of the master-regulator of mitochondrial biogenesis, PGC1α. BHB-diet ameliorated MI-induced downregulation of PGC1α, restored mitochondrial respiration, and prevented mitochondrial calcium overload. By analyzing cardiac human specimens, we discovered that Histone 3 lysin 26 dimethylation and lysin 36 methylation (H3K26me2/H3K36me) were significantly higher in human heart samples from patients with HFrEF compared to healthy controls; similar findings were observed in MI hearts compared to sham. BHB diet downregulated H3K26me2/H3K36me in murine hearts. Chromatin immunoprecipitation of H3K26me2/H3K36me revealed a PGC1α promoter enrichment. H3K26me2/H3K36me was also upregulated after ischemia in vitro and was accompanied by a decrease in PGC1α expression, dampened mitochondrial respiration, and decreased mitochondrial mass. Histone methyltransferase inhibition precluded PGC1α downregulation after ischemia mimicking BHB effect.In this study, we demonstrated for the first time that BHB mitigates HFrEF. This effect is mediated via reversing the epigenetic silencing of PGC1α with the subsequent restoration of mitochondrial function.
Abstract P3081: Glypican 3 Regulates Diabetes Induced Mesenchymal Stromal Cells Dysfunctions
Authors: Darukeshwara Joladarashi, Charan T Gurrala, Ajit Magadum, Maria Cimini, Vandana Mallaredy, Carolina Gonzalez, Anna Maria Lucchese, May Truongcao, Chunlin Wang, Cindy Benedict, Zhongjian Cheng, Raj Kishore
Journal: Circulation Research (2022)

Mesenchymal stromal cells (MSC) based therapies are considered as an ideal stem cell-based treatment for cardiovascular diseases due to their immunosuppressive characteristics, anti-inflammatory properties, and differentiation potential. Diabetic microenvironment encompassing high glucose, inflammation, hypoxic conditions, and reactive oxygen species content has deleterious effects on the functionality of MSCs. The purpose of this study was to understand the molecular basis of diabetes-induced MSC dysfunction and potentially reversing these dysfunctions to enhance cell-based therapeutics for myocardial repair in diabetic patients. we isolated MSCs from bone marrow of mice from db/+ non-diabetic (WT-MSC) and diabetic mice (db/db-MSC) and examined the effect of diabetes on MSC differentiation, proliferation, angiogenesis, and immunomodulation in vitro, and their reparative functions on myocardial injury repair post-MI in mice. Compared to WT-MSC, MSCs isolated from bone marrow of diabetic mice showed impaired differentiation, decreased proliferation, reduced immunomodulatory activities and impairment to promote endothelial cell tubulogenesis. Our data also shows diminished functional activity of diabetic MSCs to improve post-MI cardiac functions. Furthermore, we found that glypican-3 (GPC3), a heparan sulfate proteoglycan, is highly upregulated in diabetic MSCs when compared to WT-MSC. GPC3 overexpression in WT-MSC showed decreased proliferation, lowers the immunosuppression activity, and reduced vascular tube formation. Interestingly, GPC3 knockdown in WT-MSC showed increased proliferation, improved the immunosuppression activity, and enhanced vascular tube formation. Our data also showed that, knockdown of GPC3 in diabetic MSCs restore their functions. In conclusion, these data suggest that diabetes increases GPC3 expression in MSC thereby impairs MSC functions under diabetic condition and knockdown of GPC3 in diabetic MSC rescued diabetes-induced dysfunctions. Ongoing studies are testing whether ex vivo GPC3 knockdown in db/db MSCs will rescue their defective cardiac reparative activities, post-MI.
Abstract P1039: Overexpressing Mitochondrial Transcription Factor A Protects Against Myocardial Stunning And Improves Mortality In A Mouse Model Of Cardiac Arrest
Authors: Cody Rutledge, Kevin Redding, Cameron Dezfulian, Brett Kaufman
Journal: Circulation Research (2022)

Background: Cardiac arrest (CA) affects over 600,000 Americans every year and is associated with overwhelming mortality. Patients who survive CA frequently develop multi-system injury, including cardiac dysfunction and reduced cardiac ejection fraction (EF). Nearly 25% of these patients die from cardiogenic shock. This cardiac injury is primarily attributed to ischemia-reperfusion injury. Mitochondria make up 30% of the heart by volume and are a major site of ischemia-reperfusion damage. Such damage affects mitochondrial DNA (mtDNA), but these changes may be limited by manipulating mitochondrial transcription factor A (TFAM). We investigated the role of cardiac-specific TFAM overexpression on cardiac function after CA in a mouse model. Methods: Wild-type (WT) and transgenic mice featuring cardiac-specific TFAM overexpression (TFAM OE) were subjected to 8-min of asystole by direct injection with potassium chloride, followed by cardiopulmonary resuscitation. Surviving mice were assessed by echocardiography at 1-day, 1-week, and 4-weeks and monitored for survival over the time frame. Hearts were collected and sent for bulk RNA sequencing as well as assessment of mtDNA copy number, mitochondrial morphology, and protein expression. Results: TFAM OE mice express 40% more TFAM than WT littermates. TFAM OE mice had protected cardiac EF (51.11±2.95%) compared to WT mice (38.49±3.76%) at one day and improved survival over 4 weeks. Bulk-RNA sequencing implicated changes to ribosomal expression and protein synthesis in the arrest TFAM OE mice. Western blot analysis of 1-day post-arrest hearts demonstrated increased expression of multiple heat shock proteins and increased phosphorylation of eukaryotic translation initiation factor 4E-binding protein (4E-BP1), suggesting that TFAM OE mice support protein translation to aid in cardiac recovery after arrest. Conclusions: Cardiac TFAM overexpression protects cardiac function and survival after cardiac arrest. Early evidence suggests that this protection may be mediated by supporting protein translation, a novel potential pathway for improving outcomes after arrest.
Abstract P3058: Cardiac-specific Deletion Of Ptp1b Induces A Global Metabolic And Lean Phenotype
Authors: Yan Sun
Journal: Circulation Research (2022)

About 13% of US adults have diabetes, and more than half of them exhibitcardiac hypertrophy and fibrosis, resulting in cardiac diastolic dysfunction,systolic dysfunction and heart failure. Obesity is the leading risk factor for type2 diabetes. The Global Burden of Disease 2019 listed the high BMI as the fifthrisk of preterm deaths for females, and the sixth for males worldwide. Thecurrent treatments for these diseases are ineffective providing an urgent needof new therapeutic targets. Protein tyrosine phosphatase 1B (PTP1B) is themaster regulator of insulin signaling and its expression in brain, heart, liver andadipose tissues are elevated in obese mice and humans. It has been reportedthat neuronal deletion of PTP1B decreased food intake, increased energyexpenditure and protected mice from diet-induced obesity. However, whetherPTP1B in peripheral tissues would also contribute to diet-induced obesityremains unclear. To test if cardiac-PTP1B plays roles in the development ofobesity, we generated cardiomyocyte-specific PTP1B knockout mice (PTP1BCM-KO mice) and fed them with high-fat diets. Our preliminary datademonstrated that, compared to control mice, the PTP1B CM-KO mice hadreduced body weight and improved glucose homeostasis. Further analysisrevealed that deletion of PTP1B in cardiomyocytes increased energyexpenditure but didn’t affect the food intake. Metabolomics data suggested fattyacid oxidation is elevated in PTP1B CM-KO mice heart, whereas the glycolysispathway is suppressed, the amount of AMP (Adenosine Monophosphate) inPTP1B CM-KO mice is elevated 86 times than control mice on HFD. Thesefindings were further verified by qPCR analysis and ELISA. PTP1B knockoutupregulated not only NAD+ (nicotinamide adenine dinucleotide) but alsoNADPH in the heart. Nicotinamide phosphoribosyltransferase (Nampt) is therate-limiting enzyme of the NAD + salvage pathway and exists in an intracellular(iNampt) and an extracellular (eNampt) form. iNampt plays a regulatory role inNAD + biosynthesis and affects energy homeostasis. eNampt has been reportedto act as a cytokine and associated with obesity and diabetes. In the PTP1BCM-KO mice, we observed a higher level of both iNampt and eNampt,suggesting a mechanism through iNampt locally and/or through eNamptsystematically. Based on these observations, we hypothesize that the deficiency of PTP1B in cardiomyocytes increases energy expenditure,protects mice from diet-induced obesity and attenuates cardiacmalfunction induced by obesity, and cardiac-PTP1B governs whole bodyenergy homeostasis through Nampt and NAD + . We will test our hypothesisin the following specific Aims: Aim1: To elucidate the role of PTP1B in cardiac function and glucosehomeostasis.Aim2: To determine if and how the deletion of cardiac-PTP1B affectenergy balance and metabolic status through iNampt locally and/oreNampt systemically.
Abstract P2098: A Novel Measure Of Myocardial Collagen Structure Using Ultrasonic Backscatter
Authors: Lindsay A Pittman, Arjun Chadha, Michelle L Milne, Charles S Chung
Journal: Circulation Research (2022)

Aging and disease are associated with dysregulation of collagen deposition and collagen degradation and crosslinking. These modifications in collagen structure are key determinants of cardiac integrity and function, making it advantageous to monitor collagen’s state throughout disease. Although myocardial fibrosis often occurs alongside both cardiac and systemic disease, monitoring myocardial collagen typically requires expensive, invasive, and/or contraindicated methods. However, collagen content has been correlated to ultrasonic backscatter, a low-cost, non-invasive index. Preliminary studies in our lab suggested collagen also dominates the anisotropy of backscatter(variation in the brightness) in a left ventricular short-axis ultrasound. The purpose of the present study was to determine a relationship between myocardial collagen structure and anisotropy of ultrasonic backscatter while using collagenase to degrade myocardial collagen networks. Hearts were excised from Sprague Dawley rats and perfused with a collagenase-containing solution for either 10 (n=7) or 30 minutes (n=7) or control solution for 30 minutes (control n=8). Serial ultrasound images were acquired throughout collagenase digestion and ultrasonic backscatter was assessed where the collagen is primarily aligned perpendicular to the angle of insonification (bright on ultrasound image), and where collagen is primarily aligned parallel to the angle of insonification (darker on image). Our data suggested that collagenase digestion reduced backscatter anisotropy within the myocardium (p&lt;0.001) with the lateral and septal walls (collagen parallel to ultrasound) showing the greatest change in backscatter intensity. Histology (Trichrome staining) and biochemistry (hydroxyproline assay) suggests that collagen remains present but its crosslinking is altered within 10 minutes (p&lt;0.047). These data suggest that myocardial collagen fiber orientation and crosslinking of collagen correlates with the anisotropy of ultrasonic backscatter. Thus, anisotropy of ultrasonic backscatter could potentially be used to assess collagen crosslinking and deposition.